Refrigeration method



Sept. 10, 1940. A. w. WOOD REFRIGERATION METHOD Filed April 8, 1959INVENTOR ARTHUR W. Wooo- ATTORNE WITNESSES:

Patented Sept. 10, 1940 UNITED STATES PATENT orrics REFRIGERATION METHODPennsylvania Application April 8, 1939, Serial No. 268,742

Claims.

My invention relates to refrigeration apparatus and to a method forcharging refrigeration apparatus with refrigerant and lubricant.

Before a closed refrigerating system is charged,

5 t is necessary for several reasons to remove all noncondensablegases,'such as, for example, air from the refrigerating system. Thepresence of noncondensable gases will cause high head pressures in thehigh side of the system so that the eiliciency of the system will beimpaired and, if large amounts of non-condensable gases are present, themachine may even cease to operate. Furthermore, non-condensable gasesand air in the system may cause oxidation and deterioration of certainparts thereof. Again, the non-condensable gases and air sometimes reactwith the lubricant or refrigerant to form water or acids with the resultthat the water or acids combine with other chemicals in the system andcause deterioration, oxidation and rusting of the parts of the system.In hermetically sealed systems wherein the motor and compressor arecontained within a sealed casing, the presence of non-condensable gasesor air may form chemical combinations, with the refrigerant andlubricant which deleteriously affect the insulation on the windings ofthe motor, etc. It is, therefore, necessary to completely evacuatenon-condensable gases from the system before it is placed in the fieldcharged with refrigerant and lubricant.

In the copending application of Anderson and McCloy, Serial No. 156,162,filed July 28, 1937, for Refrigeration apparatus and method, andassigned to the assignee of the present application,

an evacuating and charging system is disclosed wherein the closed systemis partially evacuated by operation of the compressor with the highpressure side of the system open to atmosphere and wherein a containeris attached to the system filled with the exact refrigerant chargetherefor. The liquid refrigerant in the container enters the system andthe compressor is operated to remove the remaining non-condensable gasesfrom the system and collect them in said container. One outstandingadvantage of the system set forth in the aforesaid Anderson and McCloyapplication is that the evacuation and charging may be readilyconveyorized and the method disclosed, therefore, is particularlyapplicable to large production methods. Other advantages of the systemdisclosed in the Anderson and McCloy application are that very closecontrol of the charge may be obtained and that evacuation is effectedcompletely and with- 5 out independent evacuating apparatus. However,

on a small production scale the expense of a completely conveyorizedassembly may not be justified. In such instances it becomes important toevacuate "and charge quickly so that time and space may be conserved.

It is, therefore, an object of this invention to obtain many of theadvantages of the evacuating and charging system disclosed by Andersonand McCloy in their aforesaid application and to effect such evacuationand charging in a shorter period of time.

It is also an object of the invention to effect accurate charging of arefrigerating system and furthermore to insure substantially completeremoval of non-condensable gases from the system.

It is still another object of the invention to provide an evacuating andcharging system for refrigerating units in which several units may beevacuated and charged at one time with a minimum of equipment.

It is still a further object of the invention to provide a charging andevacuating method which is particularly adaptable to hermetically sealedrefrigerating systems and particularly wherein a continuously openrestricting device is disposed between the condenser and evaporator ofthe system.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in accordance with theaccompanying drawing, forming a part of this application, in which thesingle figure of the drawing illustrates a compression refrigeratingsystem to which my invention may be applied and also shows an enlargedcharging container, as well as the vacuum pump utilized in practicing myinvention.

Referring specifically to the drawing, numeral l designates a sealedmotor-compressor unit of a refrigerating system which embodies acompressor 2 driven by a motor 3, both of which are contained in asealed casing 4 containing a lubricant 5. The compressor illustrated isof the type wherein a piston 6 is reciprocated through a crank 'l. Alubricant scoop 8 dips into the lubricant 5 and splashes it over theworking parts of the motor and compressor. The motor 3 includes a rotor9 and field windings II, the latter preferably being formed of coppercovered with suitable insulation, such as cotton, enamel or the like.

In operation as a refrigerating system, refrigerant vapor is withdrawnby the compressor 2 from an evaporator I! through a conduit I3 whichopens into the sealed casing 4 at N. The refrigerant vapor enters thecompressor 2 through 65 compressor 2 is conveyed to a condenser l3through a conduit ll, wherein the compressed rei'rigerant is cooled andcondensed,-the cooling condensable gases removed therefrom and isbeingeffected by a stream of air circulated over the condenser l3 by a motordriven fan l3. Condensed refrigerant is then fed through a capillarytube i3 to the evaporator i2, the capillary tube preferably beingdisposed in heat exchange relation with the suction conduit I3. Afterevaporation in the evaporator l2, the refrigerating cycle is repeated. Asuitable control (not shown) for cycling therefrigerating system tomaintain a predetermined evaporator temperature, is ordinarily,provided.

In accordance with my invention, the refrigerating system hassubstantially all the noncharged in the following manner. A motordrivenvacuum pump 2| is connected to a vacuum header 22, to which severalrefrigerating systems are attached by conduits 23. The conduits 23 areprovided with hand valves, one of which is shown at 24. A screw driveroperated purge valve 25 is connected to the hand valve 24 by a conduit26 and is connected to the discharge conduit I! of the refrigeratingsystem by Y a conduit 21.

A container 23 for the refrigerant charge. is

connected to an upper hand valve 23 through a conduit 3|. The hand valve23 is in turn connected to a lower hand valve 32 through a conduit 34,and the lower hand valve 32 is attached to the interior of the sealedcasing through a filler tube 35. The hand valve 32 is then closedand thevacuum conduit 23 is attached between hand valve 24 and screw drivervalve 25. The container 28 with the exact refrigerant charge by weighttherein, together with the hand valve 23, is attached to the lower handvalve 32 by conduit 34, both the valves 23 and 32 being closed at thistime. The hand valve 23 is a part of the container assembly and sealsthe refrigerant charge therein, which charge is usually placed in thecontainer at another location.

The vacuum pump 2| is then operated with the hand valve 24 and screwdriver valve 25 open, so that a vacuum is drawn from the high side ofthe refrigerating system, which includes the discharge conduit l1 andcondenser l6. At the same time, the motor 3 is energized to operate thecompressor 2. The operation of the compressor serves two usefulfunctions; first,

the oil scoop 8 agitates the lubricant 5, and noncondensable gasesoccluded in the lubricant are freed; secondly, the compressor evacuatesthe low side of the refrigerating system including the' evaporator l2,suction conduit l3 and the in- -terior of the sealed casing 4. Thecapillary tube I 3 is evacuated by both the compressor 2 and the vacuumpump 2i. It is obvious, therefore, that the evacuation process is rapidbecause the compressor 2 evacuates the low side of the system quickly,and forces the air and non-condensable gases into the highside of thesystem, where they are readily exhausted by the vacuum pump 2|. If thecompressor were not operated the vacuum pump would take a relativelylong time to evacuate the low side of the system because of therestriction of the capillary tube l3 and the compressor valves (notshown).

The vacuum pump and compressor are operated for about ten minutes,whereupon the hand valve 24 and screw driver valve 25 are closed and theconduit 26 disconnected from the screw driver valve 23, which remainsas' a part of the refrigerating system and provides a purgevalvetherefor. The two valves 23 and 32 on the container 23 are then openedand the refrigerant charge'is drawn in by the vacuiyn existing in therefrigerating system. The compressor is then operated until theevaporator. l2 frosts over and no more liquid remains in the container23. This operation usually takes less than one minute. The hand valves23 and 32 are then closed and the filler tube 33 is pinched off andsealed. The

hand valve 32 and conduit 34 are disconnected from the container 23 andhand valve 23, and the latter are returned for a new charge ofrefrigerant. Several units are preferably operated simultaneously toeffect evacuation and charging and, as stated heretofore, are allconnected to the vacuum header 22.

From the foregoing, it will be apparent that I have provided .apparatusand amethod of quickly evacuating and accurately charging refrigeratingsystems and in which the charging and evacuating apparatus is simple andinexpensive and for which a small space is required I for fairly largeproduction because of the rapidity of the process and the small amountof apparatus involved. The container 23 need only be large enough tocontain the correct charge of refrigerant, which is usually considerablyless than one pound.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited but is susceptible ofvarious changes and modifications without departing from the spiritthereof, and I desire, therefore, that only such limitations shall beplaced thereupon as are imposed by the prior art or as are specificallyset forth in the appended claims.

What I claim is:

1. The method of removing non-condensable gases from a refrigeratingsystem including a compressor, and charging the system with refrigerant,which comprises operating the compressor to effect evacuation of thelow-pressure side of the system, evacuating non-condensable gases fromthe high pressure side of the system by connecting the same to a regionunder vacuum and charging an accurately measured quantity of refrigerantinto the system thus evacuated.

2. The method of removing non-condensable gases from a refrigeratingsystem including a compressor, and charging the system with refrigerantand lubricant, which process includes evacuating non-condensable gasesfrom the system by external evacuating means, charging lubricant intothe system, agitating the lubrl-.

cant during said evacuation and charging an accurately measured quantityof refrigerant into the system after the evacaution thereof.

3. The method of removing non-condensable gases from a refrigeratingsystem including a compressor, and charging the system with refrigerant,which comprises attaching a vacuum device to the high-pressure side ofthe system to remove non-condensable gases therefrom, operating thecompressor to evacuate non-condensable gases from the low-pressure sideof the system and forcing them into the high-pressure side of the systemwhere they are removed by the vacuum device. and charging an accuratelymeasured quantity of refrigerant into the lowpressure side of the systemthus evacuated.

4. The method of removing non-condensable gases from a refrigeratingsystem including a compressor, and charging the system with retrigerant,which comprises attaching a vacuum device to the high-pressure side ofthe system to remove non-condensable gases therefrom, operating thecompressor to evacuate non-condensable gasesirom the low-pressure sideof the system and forcing them into the high-pressure side or the systemwhere they are removed by the vacuum device. and charging an accuratelymeasured quantity of refrigerant into the system thus evacuated from acontainer connected into said system and containing said accuratelymeasured quantity of refrigerant.

5. The method or removing non-condensablelimtrcmaretrigeratingsystemincludinga motor and a compressor containedin a hermeticaily sealed casing, and charging the system withrefrigerant and lubricant, which comprises first charging the systemwith lubricant which collects in a reservoir in the interior 0! saidhermetically sealed casing. operating the compressor to effect agitationof the lubricant and evacuation oi the low-pressure side of the systemincluding the interior of said hermetically sealed casing, evacuatingnon-condensable gases from the high-pressure side 0! the system byconnecting the same to a region under vacuum and charging an accuratelymeasured quantity or retrigerant into the system thus evacuated. V

ARTHUR W. WOOD.

